Update postgresql-async, with fix for 'postgres' protocol
Add heroku procfile with db url set from env var (for evolutions plugin)

Also removed db user/pwd from application.conf so that evolutions plugin
uses db url only
Rename row mapper function
Update to pgsql-async with fix for postgresql url username

See https://github.com/mauricio/postgresql-async/pull/35

Also resolve repository name conflict
Update README